Objective

Write a SQL query to identify Facebook pages that have zero likes.

Table Schema:

• pages

• page_likes

Task Requirements:

• Identify pages that have no likes (pages that don't appear in the page_likes table)
• Return only the page IDs of pages with no likes
• Sort results in ascending order by page_id
  
  

Output columns: page_id

SELECT 
    p.page_id
FROM pages p
LEFT JOIN page_likes pl ON p.page_id = pl.page_id
WHERE pl.page_id IS NULL
ORDER BY p.page_id ASC;

Explanation

Step 1: Use LEFT JOIN to Include All Pages

A LEFT JOIN returns all rows from the pages table, with matching rows from page_likes. Pages with no likes will have NULL values in the page_likes columns.

FROM pages p
LEFT JOIN page_likes pl ON p.page_id = pl.page_id

Step 2: Filter for Pages with No Likes

Apply WHERE pl.page_id IS NULL to keep only pages that had no match in page_likes.

WHERE pl.page_id IS NULL

Step 3: Sort Results

Order by page_id ascending.

ORDER BY p.page_id ASC